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LS6 stumble

Old 08-07-2016, 11:02 AM
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Default LS6 stumble

Help! I've run out of knowledge.

I have an LS6 in a '64 Chevelle that has a stumble under load. It acts like fuel starvation. If I lift, it will rev to limiter. Engine is stock internally, long tubes, mail order tune by PCM of NC. During testing last year before paint & body, no apparent problems. Idles good, revs good with no load. I do have a P0336 code and it won't do a crank relearn with Tech II scanner. Scanner showed good signal from crank and cam position sensors and no misfires. 60psi fuel pressure, plugs look lean.

Any suggestions?

Last edited by alschoon; 08-07-2016 at 11:08 AM.
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Old 08-07-2016, 01:16 PM
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Originally Posted by alschoon View Post
If I lift, it will rev to limiter.
That makes no sense. Crank position sensor is a critical sensor for proper engine operation. Figure out what is causing the code and fix it. Crank sensor relearn is not causing that code to set. Also you give no indication of the pcm being used or what vehicle platform it is programmed with. You are going to have to post a datalog with a recording of the problem to get any real help.
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Old 08-07-2016, 02:04 PM
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Stock C5Z PCM with mail order tune to remove VATS, rear O2s, raise rev limit, remove traction control.
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